sub: reimplement -spugauss as --sub-gauss

Apparently the -spugauss option was popular. The code originally
implementing this is gone (scaler stuff in spudec.c). Reimplement it
using libswscale to scale and blur image subtitles if the --sub-gauss
option is set.

The code does some rather lazy padding to allow the blur to spread
pixels past the original image bounding box. (This problem exists with
normal bilinear scaling too, but is barely noticable.)

Technically, this doesn't just blur subtitles, but anything RGBA (or
indexed) that enters the OSD rendering path. But only image subtitles
produce these OSD formats currently, so no explicit check is done to
prevent blurring in other cases.

1 files changed, 5 insertions, 0 deletions

diff --git a/sub/sub.c b/sub/sub.c
index dd8c887b4c..66ee6ea42c 100644
--- a/sub/sub.c
+++ b/sub/sub.c
@@ -172,6 +172,8 @@ static void render_object(struct osd_state *osd, struct osd_object *obj,
                           const bool formats[SUBBITMAP_COUNT],
                           struct sub_bitmaps *out_imgs)
 {
+    struct MPOpts *opts = osd->opts;
+
     *out_imgs = (struct sub_bitmaps) {0};
 
     if (!osd_res_equals(res, obj->vo_res))
@@ -222,6 +224,9 @@ static void render_object(struct osd_state *osd, struct osd_object *obj,
     if (formats[SUBBITMAP_RGBA] && out_imgs->format == SUBBITMAP_INDEXED)
         cached |= osd_conv_idx_to_rgba(obj->cache[0], out_imgs);
 
+    if (out_imgs->format == SUBBITMAP_RGBA && opts->sub_gauss != 0.0f)
+        cached |= osd_conv_blur_rgba(obj->cache[1], out_imgs, opts->sub_gauss);
+
     if (cached)
         obj->cached = *out_imgs;
 }